This invention relates to an external airbag for a vehicle.
Airbags are commonly employed to protect vehicle occupants. Recently, however, manufacturers have shown an interest in protecting a pedestrian who might be struck by a vehicle. One such system protects the pedestrian through the deployment of an airbag external of the vehicle. In the event the vehicle hits the pedestrian, a door panel on an exterior surface of a vehicle and hood opens to release a large airbag, which forms a cushion against injury for the pedestrian. Such a system has several drawbacks.
First, a door panel for an external airbag introduces a visible panel indentation on the exterior surface of the vehicle. This indentation interrupts the smooth line, finish and appearance of the vehicle hood. Accordingly, the door panel may be aesthetically undesirable.
Second, for such a system, the airbag and inflator are located underneath the door panel. Given the size of the airbag as well as the size of the inflator needed to inflate the airbag, much space is required underneath the hood to accommodate the external airbag and inflator. Because the hood extends over the engine, there is very little space available to accommodate these components.
Third, after deployment of the airbag, the airbag is typically replaced. Due to the size of the external airbag, its replacement adds significant expense to the maintenance of the protective system. It is therefore desirable to reduce this expense.
Finally, the airbag that deploys through the hood is secured through the open door panel. Accordingly, the end of the airbag that deploys out of the door panel is free to move. In the event of an accident, it would be preferable to attach the airbag in a more secure fashion to ensure that a pedestrian hit by the vehicle will not miss the airbag.
There is a need for an external airbag system that avoids the foregoing limitations.
Like existing exterior airbag systems, the present invention comprises an airbag and an airbag inflator. However, in contrast to these systems, the inventive airbag module has a unique airbag formed to be part of the top of a vehicle body panel. One wall of the airbag may be a flexible layer while another wall may be the vehicle body panel. The airbag inflator provides inflation gas to a space between the vehicle body panel and the flexible layer through a conduit, such as a port extending through the panel. In the event of a collision with a pedestrian, the inflator fills the space between the flexible layer and the vehicle body panel with inflation gas, expanding the flexible layer to form a cushion.
When not deployed, the flexible layer is attached to the outside surface of the vehicle body panel by an adhesive or by a vacuum. Because the airbag deploys from the outside surface of the body panel, no door panel is required. Moreover, no space underneath the body panel is required to store the airbag because the inventive airbag is stored on top of the body panel. The flexible layer may be transparent so as to allow color of the vehicle body panel to be seen through the layer. Alternatively, the flexible layer may match the body color of the vehicle.
The airbag has a seal between the flexible layer and the vehicle body panel to retain inflation gas between the two surfaces. The seal may extend around the periphery of the vehicle body panel so that the airbag is secured across the entire body panel rather than at one location. The vehicle body panel may be a vehicle hood.
The invention may use a replaceable pressurized gas cartridge to deploy the airbag. The stored pressurized gas will not damage the airbag during deployment. In this way, the airbag may be reusable. The airbag system is maintainable by simply replacing the gas cartridge.
The inventive airbag module is made by extending a flexible layer over a vehicle body panel. The flexible layer is sealed to the body panel. A conduit is created between the flexible layer and the body panel to permit inflation gas to pass between the two surfaces. The conduit is connected to an airbag inflator.